For example, inverter controllers with smaller sizes and lighter weights have been demanded. Accordingly, resin molding semiconductor devices mounted in inverter controllers have been reduced in size and weight. Moreover, for resin molding semiconductor devices including power semiconductor elements or substrates having electrical components such as semiconductor devices, a high withstand voltage between adjacent electrodes or higher heat dissipation has been demanded.
In a resin molding semiconductor device, heat dissipation from a chip to the top surface of a package is restricted by the heat conductivity of a resin used for molding. Thus, in Patent Literature 1, as shown in FIG. 11, a metallic case 33 covering a chip 31 is mounted on a substrate 32 and is filled with a coolant 34 in the metallic case 33. In the resin molding semiconductor device of Patent Literature 1, heat generated from the chip 31 is transmitted to the case 33 by the heat convection of the coolant 34, achieving higher heat conduction to the outside than in a conventional resin molding semiconductor device.
In a cooling system for a pulsed power semiconductor described in Patent Literature 2, heat is absorbed by a molding material containing microcapsules of a phase-change-material. FIG. 12 is a schematic cross-sectional view illustrating a semiconductor device 1001 disclosed in Patent Literature 2. The semiconductor device 1001 includes a radiator plate 1003, a substrate 1005, and elements 1007. The elements 1007 mounted on the substrate 1005 are molded with a molding material 1013. The molding material 1013 contains microcapsules of a phase-change-material 1103. For example, epoxy resin is disclosed as the molding material 1013. A heat conducting material 1009 is applied between the element 1007 and the molding material 1013. The elements 1007 and the molding material 1013 are thermally coupled by the heat conducting material 1009.